A parent or person decides differently, believes differently, or lives differently than you do.
What drives you to judge them?
Is it driven by a strong emotional reaction?
Do you desire, and believe it's possible, for everyone to be as you are and believe as you do?
Do you do it in order to derive a sense of superiority from your life, choices, and beliefs?
Does the reason change depending upon what you're judging?
I realize that we all judge, as it's human nature. We must make judgments for our own survival. However, it seems that sometimes, we waste our time judging others for trivial matters. We find ourselves resorting to derision and cruelty when reacting to something that doesn't affect us, or truly cause harm to anyone.
"What is a man, if chief good, and market of his time be but to sleep and feed? A beast, no more." Hamlet